Ceramic composites, which may be used in a number of applications, typically include a ductile phase embedded in a ceramic material.
Existing methods of making ceramic composites typically include embedding ceramic powders in a polymer phase. Due to the presence of a polymer phase, the flexibility of these ceramic composites is generally restricted to mild temperatures (e.g., 200° C. or less). Moreover, strong ionic/covalent bonding typically imparts conventional ceramic composites with strong mechanical properties while undermining the composites' flexibility.
These limitations can be disadvantageous, because many applications may benefit from or require compliant and/or flexible ceramic composites. The ability to deform flexibly is desirable for many advanced applications, such as thermal protection systems and battery materials.
Carbon nanotubes (CNTs) are known for their remarkable intrinsic mechanical, electrical, and thermal properties. As a result, CNTs have been used to improve the electrical properties of composite materials, but the CNTs can be difficult to disperse, completely or otherwise, into matrices, including ceramic matrices. Existing methods for making a composite containing ceramic materials and carbon nanotubes are based on mixing carbon nanotubes in ceramic powders or ceramic polymeric precursors directly. These methods, however, can produce composites containing only a limited volume fraction of carbon nanotubes in the ceramic matrix.
There remains a need for improved composite materials and methods of making composite materials containing carbon nanotubes and a ceramic matrix, including composite materials that include a relatively high volume fraction of carbon nanotubes, are flexible, and/or have a relatively high electrical conductivity.